SA9103C
7. Software flow
In an application in which all the registers must be accessed, the software loop
illustrated below can be implemented.
LOOP
∧
READ FREQUENCY COMMAND
DELAY OF 8 MAINS PERIODS
RECEIVE FREQUENCY
READ ACTIVE COMMAND
DELAY OF 8 MAINS PERIODS
RECEIVE ACTIVE
READ REACTIVE COMMAND
DELAY OF 8 MAINS PERIODS
RECEIVE REACTIVE
READ VOLTAGE COMMAND
DELAY OF 8 MAINS PERIODS
RECEIVE VOLTAGE
The SA9103C integrated circuit transmits the register values only after completion
of the current measurement cycle (8 mains periods maximum).
The delay of 8 mains periods can be calculated from the period value of the
frequency returned by the initial read, and updated with each subsequent reading
of frequency.
Each successive read of the registers takes place regularly at intervals of 4 blocks
of 8 mains cycles. This time and the difference between successive energy register
values can be used to calculate power.
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